Mk2 with 2.5Di conversion. Temp gauge not working

[103keef]

Fitted a 2.5Di from a 2000 MK5.
All wired up and working apart from the Temperature gauge.
I'm using the MK5 plastic Stat Housing and Switch.
Original was a single wire Temp Switch but the MK5 has a two wire switch. I'm assuming this is because it needs an earth being in the plastic housing.
I have the Connector Plug and bit of wiring from the MK5.
I've tried earthing the Black wire and connecting the White with Red Trace to the MK2's original single wire, which is also White/Red. Coincidence?
Anyway, gauge doesn't move and was working fine on original York Engine.
Any ideas?

[Muttley]

Fit a Mk3 thermostat housing with the single wire sender unit.

[PIO]

Any joy with this - Thanks

[captinbob]

I had the same issue. You need to use the mk2 single wire sender but you need to connect the black wire to the body of the sender (i used a crimp on eye of the same diameter as the sender threads) and the red and white wire to the terminal on the sender